After struggling with an eye infection -- which has likely been exacerbated by the studio lights and makeup -- since the start of the games, Costas stepped down from his platform in Sochi on Tuesday.

While "in isolation" in a Sochi hotel, as interviewer Ryan Seacrest described it, Costas gave an optimistic update on his recovery while calling in to Seacrest's morning radio show.

"Here's the thing -- I feel fine, which seems weird," he said with high spirits. "If you could remove my eye from the equation, which I admit is a rather large factor, I feel fine. I'm not really sick, but I have this eye infection, which has gone from my left eye to my right."

The NBC personality has hosted every Olympic Games since 1992 and has a seemingly encyclopedic knowledge of myriad obscure Olympic sports and athletes. Meanwhile, Matt Lauer has filled in as anchor for the past two nights.

"I did the first five nights wearing glasses, even though people could see how red and swollen my eyes were," he continued. "I didn't care because I could still function. I could still read the notes I had to read on the athletes and find my way around the studio. But then in the last 36 hours, it got to the point my vision became so blurry and sensitive to light, I can't even be in regular room light, let alone studio light. I couldn't be of any use to them."

He compared the NBC Olympics broadcasting team to the athletic teams he reports on, noting that he would normally continue on if dealing with a bad back or a headache, for the sake of the team. But with an eye infection, "you have involuntary reactions, and it's simply impossible."

Despite his current condition, he was full of humor: "When something like this -- and this is a bad pun -- both I and the situation have gone viral," he joked of his health status becoming a trending topic on the Internet, also adding that he and the NBC teams have received thousands of emails and calls from fans offering both clinical and home remedies. "Everybody's trying to help, and they're killing me with kindness."

Costas believes he'll soon return to the field to report on the Olympics in Sochi. "In sports, there's a term that they use for people who are on the injured list -- they say, 'He's day-to-day.' And I am day-to-day. I'm hoping that I'm back by the weekend and I certainly think I'll be able to do the second half of the games. The virus, they tell me, won't run its course for two or three weeks, but the symptoms will crest at their worst and start to get better pretty soon. As soon as the symptoms get to the point where I can be in the studio, I'll be there."